Microbial GeneticsMicrobial Genetics

I. Structure and function of DNA and genesI. Structure and function of DNA and genes

II. Gene expression in bacteriaII. Gene expression in bacteria

III. Mutation and variationIII. Mutation and variation

IV. Horizontal gene transfer in bacteriaIV. Horizontal gene transfer in bacteria

Nucleotides of __________________ ___________ (RNA)Nucleotides of __________________ ___________ (RNA)

Nucleotides of ____________________ Acid (DNA)Nucleotides of ____________________ Acid (DNA)

Note the numbering of the carbon atomsNote the numbering of the carbon atoms

“Growth” (__________________________) of a single DNA strand

“Growth” (__________________________) of a single DNA strand

5’5’

5’5’

3’3’

3’3’

3’3’

5’5’

Note: this is __________Note: this is __________ But RNA also But RNA also polymerizes like thispolymerizes like this

“_____________” arrangement of the two strands of a DNA molecule“_____________” arrangement of the two strands of a DNA molecule

5’ end5’ end

5’ end5’ end

3’ end3’ end

3’ end3’ end

The ‘base’ component of a nucleotide -- ________________

The ‘base’ component of a nucleotide -- ________________

AdenineAdenineAA

GuanineGuanineGG

The ‘base’ component of a nucleotide -- _________________

The ‘base’ component of a nucleotide -- _________________

CytosineCytosineCC

ThymineThymineTT

UraciUracillUU

Note that this is Note that this is riboseribose. What would deoxyadenosine . What would deoxyadenosine triphosphate (dATP) look like?triphosphate (dATP) look like?

or or ______________

The amount of adenine = the amount of ___________ The amount of adenine = the amount of ___________ and the amount of cytosine = the amount of and the amount of cytosine = the amount of ____________ in a cell____________ in a cell

DNA Secondary StructureDNA Secondary Structure

See text, Fig. 9.4See text, Fig. 9.4

Overview

DNA replicationDNA replication

Replication of the bacterial ________________Replication of the bacterial ________________

DNA Replication -- First StepsDNA Replication -- First Steps

DNA Replication -- First Steps (cont)DNA Replication -- First Steps (cont)

DNA structure and replicationDNA structure and replication

QuickTime™ and aCinepak decompressor

are needed to see this picture.

Flow of genetic information in cells

Information processing in _____________Information processing in _____________

Information processing in _____________Information processing in _____________

Text, Fig. 9.18

Promoter regionPromoter region -- -- where where RNA polymeraseRNA polymerase binds binds

to initiate _____________________to initiate _____________________

One gene ---> one _______________One gene ---> one _______________

DNA Transcription

DNA Transcription

Transcription Animation

http://www.microbelibrary.org/FactSheet.asp?http://www.microbelibrary.org/FactSheet.asp?SubmissionID=378SubmissionID=378

Text, Fig. 9.13

Text, Fig. 9.13

Text, Table 9.3

The RibosomeThe Ribosome

A ribosome's true colors. (Top) The large subunit of the ribosome seen from the viewpoint of the small subunit, with proteins in purple, 23S rRNA in orange and white, 5S rRNA (at the top) in burgundy and white, and A-site tRNA (green) and P-site tRNA (red) docked according to (5).

(Bottom) The peptidyl transfer mechanism catalyzed by RNA

Translation: tRNATranslation: tRNA

________________ RNA (tRNA)________________ RNA (tRNA)

Prokaryotic TranslationProkaryotic Translation

AnimationAnimation

http://www.microbelibrary.org/FactSheet.asp?http://www.microbelibrary.org/FactSheet.asp?SubmissionID=379SubmissionID=379

Translation: the ribosomeTranslation: the ribosome

Translation: _______________Translation: _______________

Translation: Elongation (cont.)Translation: Elongation (cont.)

Translation: Elongation (cont.)

TranslationTranslation

QuickTime™ and aCinepak decompressor

are needed to see this picture.

Text, Fig. 9.17

Replication problemReplication problem

Give the sequence of the strand replicated from the following Give the sequence of the strand replicated from the following strand:strand:

5’- GTT ATT CCC GTA ATC GGC TAG - 3’5’- GTT ATT CCC GTA ATC GGC TAG - 3’

Answer:Answer:

3’- __________________________________ - 5’3’- __________________________________ - 5’

Which direction relative to the original strand, left or right, would Which direction relative to the original strand, left or right, would the polymerase move as it makes this strand?the polymerase move as it makes this strand?

Answer: _____________Answer: _____________

Transcription ProblemTranscription Problem

AAssume that the strand just produced is the ssume that the strand just produced is the sense strandsense strand (the strand encoding the mRNA):(the strand encoding the mRNA):

3’- CAA TAA GGG CAT TAG CCG ATC - 5’3’- CAA TAA GGG CAT TAG CCG ATC - 5’

What would be the sequence of the mRNA transcript of this portion of the gene? Be sure and include 5’-3’ orientation.

Answer:

____________________________________

Translation problemTranslation problemTranslate your transcript using the following codon tableTranslate your transcript using the following codon table

5’- GUU AUU CCC GUA AUC GGC UAG - 3’

Answer:

____ ____ ____ ____ ____ ____ ____

ProblemProblemHere is a portion of the sense strand of a gene:

5’ – T A C C G A C C T T T G A G A A C T T G A – 3’

1) What would be the sequence of the strand which is replicated from this strand (be sure to note the 5’-3’ orientation of the strand)?

2) Which direction would the DNA polymerase move as it replicates this (sense) strand:

a. <---------- Left

b. ----------> Right

3) What would be the sequence of the mRNA transcript of this portion of the gene (include orientation)?

4) Translate using the codon table.4) Translate using the codon table.